What could cause a sharp pain on shaft/head of penis?

Here are some ...: The provided info is not enough to offer sensible answer. But, roughly, one can say the pain is related with local irritation from urethra - especially prostate urethra or from so-called referring ache from disorders of nearby nerves, muscles, or joints. To differentiate what they may be, bring the info on the onset, degree, duration, interval, evolution, & progress of the pain over time to Doc...